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Thursday, 14 July 2016

Update from Fukushima - 07/13/2016

13 July, 2016NHK reports
that the decommissioning authority in
charge of dealing with the aftermath of the Fukushima disaster is now
considering a sarcophagus to entomb the failed reactors rather than
attempting to remove the melted fuel, debris and buildings.

The
authority told NHK they would still consider the two fuel removal
techniques but they are adding the sarcophagus option to the list.
They did not elaborate about why it is now being officially added to
the considered options for the plant.

The
idea of leaving the plant as is and creating a sarcophagus around the
three melted down reactors is extremely problematic. The groundwater
issue is just one problem that would be a permanent problem. Even the
ice wall if it eventually works as planned can only operate for a few
years. Erosion and groundwater flows would create a permanent problem
for the ocean and the region around the plant. This would also leave
the fuel and crumbling buildings in place. Building failures,
radioactive dust and fuel debris would all still be in place. This
would need to be managed not just due to aging but further natural
disasters such as typhoons and tsunami. Current problems include fuel
fragments that have been found in unit 1′s torus room basement
water. These have been a concern as groundwater flows through these
basements that if improperly managed, more of these fuel fragments
could leave the basement into the groundwater.....[ ]

The
government body charged with decommissioning the reactors at the
Fukushima Daiichi nuclear plant says it remains committed to removing
the fuel but sealing off the buildings that house them could be an
option.

The Nuclear Damage Compensation and Decommissioning
Facilitation Corporation issued its latest report Wednesday on its
plan.

is
meant that most of the radioactive material was not dissolved in rain
and running water… The
particles also concentrated the radioactive caesium (Cs),
meaning that in some cases dose effects of the fallout are still
unclear… Japanese geochemists… analysed samples collected from
within an area up to 230
km from the FDNPP…
[I]t had been anticipated that most of the radioactive fallout would
have been flushed from the environment by rainwater. However… most
of the radioactive caesium in fact fell to the ground enclosed in
glassy microparticles…
[T]hese particles… formed during the molten core-concrete
interaction inside the primary containment vessel in the Fukushima
reactor units 1 and/or 3. Because of the high Cs content in the
microparticles, theradioactivity
per unit mass was as high as ~4.4×10^11 Bq/g [440,000,000,000,000
Bq/kg]…
Analysis from several air filters collected in Tokyo on 15 March 2011
showed that 89%
of the total radioactivity was present as a result of these
caesium-rich microparticles,
rather than the soluble Cs, as had originally been supposed.

Discovery
(Seeker),
Jun 27, 2016: Fukushima
Accident Rained Glass Particles on Tokyo…
Most of the radioactive fallout that descended upon downtown Tokyo in
the days after the March 2011 accident [was] glass microparticles —
essentially, glass-filled soot. As a result, the fallout, which
contained concentrated radioactive cesium, wasn’t
dissolved by rainfall, and probably lingered in the environment…
Japanese scientists thought that most of it would be washed away by
rainwater. Instead, analysis… revealed that most of the radioactive
cesium in fact fell to the ground enclosed in glassy microparticles.

ANI,
Jun 28, 2016: Research
indicates Fukushima radioactive fallout may be worse
than expected… Most
of the radioactive fallout, which landed
on downtown Tokyo a
few days after the Fukushima accident, was concentrated and deposited
in non-soluble glass microparticles, as a type of ‘glassy soot’…

Inverse,
Jun 26, 2016: Radioactive
“Glassy Soot” Fell Over Tokyo After the Fukushima Meltdown…
The findings… show that the radioactive fallout… has
been poorly understood.
Previously, it was assumed that most of the radiation that fell
dissolved in rain. This would mean that it would wash out of the soil
and through the environment… These tiny
glass particles entered the air and fell as soot on the surrounding
region.
Because the radioactive molecules are contained in an insoluble
medium, they
will not wash out of the soil with rainwater to
the same extent… Beyond the consequences for the environment, there
are significant consequences for human health.
Breathing caesium encased in glass particles may have a very
different impact from exposure to it as radioactive rain…

Dr
Satoshi Utsunomiya, Kyushu Univ.:
“This
work changes some of our assumptions about the Fukushima fallout…
This may mean that our
ideas of the health implications should be modified“.

Prof.
Bernd Grambow, Director of SUBATECH laboratory, France:
“[The observations]presented
here are extremely important.
They may change our understanding of the mechanism of long
range atmospheric mass transfer of radioactive caesium from the
reactor accident at Fukushima to Tokyo,
but they may also change the way we assess inhalation doses from the
caesium microparticles inhaled by humans. Indeed, biological half-
lives of insoluble caesium particles might
be much larger than that of soluble caesium“.